JPH02277306A - Sound volume control circuit - Google Patents

Abstract

PURPOSE:To avoid the sound volume from being suddenly increased at application of power by operating a time constant circuit so as to change the sound volume slowly for a while when the power is turned from OFF to ON. CONSTITUTION:A time constant circuit 2 outputs an output of a sound volume control circuit 1 as it is normally (after the period of the time constant when power is applied) and converts an output of the sound volume control circuit 1 into a voltage proportional to the time after application of power and outputs the result. Thus, an amplifier 3 is controlled by an output of the time constant circuit 2 to vary the sound volume slowly for the period of the application of time constant. Thus, the sound volume control is changed in response to the power control input to control the operation of a cathode ray tube of a television receiver and the operation of a sound circuit similarly.

Description

[Detailed description of the invention] Industrial applications The present invention is used in color television receivers and the like.

Regarding the volume control circuit, this prevents the sound from suddenly becoming loud when the power is turned on.

BACKGROUND OF THE INVENTION In conventional volume control circuits, the power supply control input and the volume control circuit are controlled independently.

That is, there was no particular relationship between the volume control circuit and the power supply control circuit.

A conventional volume control circuit and power control input will be described below with reference to the drawings.

First, FIG. 3 is a block diagram of a conventional volume control circuit, power control input, and power supply circuit. In FIG. 3, 5 is a volume control circuit, 6 is an amplifier whose audio output is controlled by the output of the volume control circuit 5, and 7 is a power supply circuit that turns on/off the power of the entire system by a power supply control input. be.

The operation of the conventional volume control circuit configured as described above will be explained below using FIG. 3.

First, reference numeral 7 is a power supply circuit that supplies power to the entire system through a power control input, and when the power is turned on, power is supplied to the volume control circuit 5 and the amplifier 6 at the same time. 5 is a volume control circuit that controls the volume by a volume control input, but even if there is a volume control input, the output does not change immediately to allow the desired volume to be adjusted, and the output does not change immediately until it reaches the minimum volume from the maximum volume. It takes a few seconds. Further, the output state of the volume control circuit 5 when the power is turned on maintains the previous state.

Problem to be Solved by the Invention However, in the operation described above, the amplifier 6 starts operating immediately after power is supplied, so if you have been listening at high volume before, a loud sound will come out as soon as the power is turned on, but the TV reception Normally, the screen of a CRT does not appear on the screen for about 10 seconds, so the sound is loud and the screen is not displayed. For example, if you don't want the sound to be too loud in the morning, you may want to lower the volume. There will be a lot of noise for a few seconds in between.

In order to solve the above problems, the present invention provides a time constant circuit,
The present invention provides a volume control circuit that realizes a function of slowly changing the open volume for a while after the power is turned on.

Means for Solving the Problems In order to solve the above problems, the volume control circuit of the present invention has the following features:
This device has a configuration in which a time constant circuit is operated when the power is turned on from OFF in response to a power control input, and the volume is slowly changed for a while.

Operation The present invention is configured as described above to prevent sudden loud noises from being produced when the power is turned on.

Embodiment Below, a volume control circuit according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a volume control circuit according to the present invention.

In FIG. 1, l is a volume control circuit, and 2 is a time constant circuit activated by the power supply control input. Normally, the output of the volume control circuit 1 is output as is, and the time constant period after the power is turned on is is a time constant circuit that converts the output of the volume control circuit 1 into a voltage value proportional to the time after the power is turned on, 3 is an amplifier whose audio output is controlled by the output of the time constant circuit 2, and 4 is an amplifier. This is a power supply circuit that supplies power to the entire system through power control input.

The operation of the volume control circuit configured as above will be explained below with reference to FIGS. 1 and 2.

In Fig. 1, the time constant circuit 2 outputs the output of the volume control circuit 1 as it is during the normal time (after the time constant period after the power is turned on), and the output of the volume control circuit 1 during the time constant period after the power is turned on. This is a circuit that converts the output into a voltage value proportional to the time after the power is turned on and outputs it, and by controlling the amplifier 3 with the output of the time constant circuit 2, a change in volume as shown by the solid line in FIG. 2 can be realized.

In FIG. 2, the time t1 from when the power is turned on until the volume reaches the level heard last is about 10 seconds until the cathode ray tube operates normally.

In this embodiment, the control of the time constant circuit 2 has been explained as being related only to the power supply control input. If there is a volume control input to increase the volume during
The time constant circuit 2 may be controlled by the volume control circuit 1 in such a way that if the volume control input for volume down is exhausted during that time, the volume level is fixed at the current volume level.

Effects of the Invention As described above, the present invention provides a time constant circuit when the power is turned on, and changes the volume control according to the power control input, thereby controlling the operation of the cathode ray tube and the audio circuit of the television receiver. It can be controlled in the same way, and it also has the effect of preventing sudden loud noises immediately after the power is turned on.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a volume control circuit according to an embodiment of the present invention, Fig. 2 is a timing diagram for explaining the operation when the power is turned on, and Fig. 3 is a block diagram of a conventional volume control circuit and a power supply control circuit. It is. 1...Volume control circuit, 2...Time constant circuit, 3...Amplifier, 4...Power supply circuit.

Claims (1)

[Claims] It is characterized by comprising a volume control circuit, a time constant circuit that controls the output of the volume control circuit using a power supply control input, and an audio amplifier that is controlled by the output of the volume control circuit that is supplied through the time constant circuit. Volume control circuit.